docs: def reassign_label(self, label, new_label, relabel=False):
          """
          Reassign a label number to a new number.
  
          If ``new_label`` is already present in the segmentation image,
          then it will be combined with the input ``label`` number.
  
          Parameters
          ----------
          labels : int
              The label number to reassign.
  
          new_label : int
              The newly assigned label number.
  
          relabel : bool, optional
              If `True`, then the segmentation image will be relabeled
              such that the labels are in consecutive order starting from
              1.
  
          Examples
          --------
          >>> from photutils import SegmentationImage
          >>> segm = SegmentationImage([[1, 1, 0, 0, 4, 4],
          ...                           [0, 0, 0, 0, 0, 4],
          ...                           [0, 0, 3, 3, 0, 0],
          ...                           [7, 0, 0, 0, 0, 5],
          ...                           [7, 7, 0, 5, 5, 5],
          ...                           [7, 7, 0, 0, 5, 5]])
          >>> segm.reassign_label(label=1, new_label=2)
          >>> segm.data
          array([[2, 2, 0, 0, 4, 4],
                 [0, 0, 0, 0, 0, 4],
                 [0, 0, 3, 3, 0, 0],
                 [7, 0, 0, 0, 0, 5],
                 [7, 7, 0, 5, 5, 5],
                 [7, 7, 0, 0, 5, 5]])
  
          >>> segm = SegmentationImage([[1, 1, 0, 0, 4, 4],
          ...                           [0, 0, 0, 0, 0, 4],
          ...                           [0, 0, 3, 3, 0, 0],
          ...                           [7, 0, 0, 0, 0, 5],
          ...                           [7, 7, 0, 5, 5, 5],
          ...                           [7, 7, 0, 0, 5, 5]])
          >>> segm.reassign_label(label=1, new_label=4)
          >>> segm.data
          array([[4, 4, 0, 0, 4, 4],
                 [0, 0, 0, 0, 0, 4],
                 [0, 0, 3, 3, 0, 0],
                 [7, 0, 0, 0, 0, 5],
                 [7, 7, 0, 5, 5, 5],
                 [7, 7, 0, 0, 5, 5]])
  
          >>> segm = SegmentationImage([[1, 1, 0, 0, 4, 4],
          ...                           [0, 0, 0, 0, 0, 4],
          ...                           [0, 0, 3, 3, 0, 0],
          ...                           [7, 0, 0, 0, 0, 5],
          ...                           [7, 7, 0, 5, 5, 5],
          ...                           [7, 7, 0, 0, 5, 5]])
          >>> segm.reassign_label(label=1, new_label=4, relabel=True)
          >>> segm.data
          array([[2, 2, 0, 0, 2, 2],
                 [0, 0, 0, 0, 0, 2],
                 [0, 0, 1, 1, 0, 0],
                 [4, 0, 0, 0, 0, 3],
                 [4, 4, 0, 3, 3, 3],
                 [4, 4, 0, 0, 3, 3]])
          """
  
          self.reassign_labels(label, new_label, relabel=relabel)